propertiessheetlistener.java

jboss规则引擎

package org.drools.decisiontable.parser.xls;

/*
 * Copyright 2005 JBoss Inc
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

import org.drools.decisiontable.parser.SheetListener;

/**
 * Reads an Excel sheet as key-value properties.
 * 
 * Treats the first non-empty cell on a row as a key and any subsequent
 * non-empty cell as a value. Any cells defined after the second cell are
 * ignored as comments.
 * 
 * Could be easily adapted to accept multiple values per key but the semantics
 * were kept in line with Properties.
 * 
 * @author <a href="mailto:[e-mail]"> Shaun Addison </a>
 * 
 */
public class PropertiesSheetListener
    implements
    SheetListener {

    private static final String EMPTY_STRING   = "";

    private final Map                 _rowProperties = new HashMap();

    private final Properties          _properties    = new Properties();

    /**
     * Return the key value pairs. If this is called before the sheet is
     * finished, then it will build the properties map with what is known.
     * Subsequent calls will update the properties map.
     * 
     * @return properties
     */
    public Properties getProperties() {
        finishSheet(); // MN allows this to be called before the sheet is
        // finished, as
        // some properties are used whilst the sheet is being parsed.
        return this._properties;
    }

    /*
     * (non-Javadoc)
     * 
     * @see my.hssf.util.SheetListener#startSheet(java.lang.String)
     */
    public void startSheet(final String name) {
    }

    /*
     * (non-Javadoc)
     * 
     * @see my.hssf.util.SheetListener#finishSheet()
     */
    public void finishSheet() {
        for ( final Iterator iter = this._rowProperties.keySet().iterator(); iter.hasNext(); ) {
            final String[] keyValue = (String[]) this._rowProperties.get( iter.next() );
            this._properties.setProperty( keyValue[0],
                                     keyValue[1] );
        }
    }

    /**
     * Enter a new row. This is ignored.
     * 
     * @param rowNumber
     *            The row number.
     * @param columns
     *            The Colum number.
     */
    public void newRow(final int rowNumber,
                       final int columns) {
        // nothing to do.
    }

    /*
     * (non-Javadoc)
     * 
     * @see my.hssf.util.SheetListener#newCell(int, int, java.lang.String)
     */
    public void newCell(final int row,
                        final int column,
                        final String value,
                        final int mergedColStart) {
        if ( emptyCellValue( value ) ) {
            return;
        }
        final Integer rowInt = new Integer( row );
        if ( this._rowProperties.containsKey( rowInt ) ) {
            final String[] keyValue = (String[]) this._rowProperties.get( rowInt );

            if ( keyValue[1] == PropertiesSheetListener.EMPTY_STRING ) {
                keyValue[1] = value;
            }
        } else {
            final String[] keyValue = {value, PropertiesSheetListener.EMPTY_STRING};
            this._rowProperties.put( rowInt,
                                keyValue );
        }
    }

    private boolean emptyCellValue(final String value) {
        return value == null || value.trim().equals( "" );
    }

}